@fazelstudio/codemirror-lang-lua

This package implements Lua 5.4 language support for the CodeMirror code editor: a full Lezer native grammar covering chunks, blocks, assignments, control structures (if/while/repeat/for), function declarations, local declarations, table constructors, string literals (including long strings [[...]]), numeric literals (hex, binary & underscore 1_000_000), comments (-- & --[[...]]), labels (::label::), goto, and production-grade additions — syntax highlighting, autocomplete (stdlib + snippets), indentation, folding & bracket matching — compatible with any CodeMirror 6 theme.

This code is released under an MIT license.

Features

Core (v0.1 → v1.0 perfect)

• Full Lua 5.4 syntax (Lua Reference Manual §3.1/3.3/3.4 + EBNF)
• Table constructors (array-style, record-style, mixed, ,/; separators, bracket keys)
• Long strings ([[...]], [=[...]=], [===[...]==]) with level matching via external tokenizer
• Numeric literals: decimal, float, hex (0xFF + 0x1.8p10), binary (0b1010), underscore separators (1_000 / 0xFF_FF / 0b1010_0101)
• Comments: line (--) & block (--[[...]] with levels --[=[) + Shebang #!/usr/bin/env lua
• Labels (::retry::) & goto, break, return
• Multiple assignment / multiple return, vararg ..., attributes <const> <close>
• Syntactic sugar: print "hello", type{} , obj:method "arg" + chaining require "a".field:sub():call()
• Call-chain fix (1.0): f()() / a("x").b() / require("x").y() / foo().bar():baz() now 0-error (was ⚠ before)
• Precedence climbing: or < and < compare < | < ~ < & < <<>> < .. (right) < + - < * / // % < unary < ^ (right)

Editor (new in 1.0 — complex)

• Autocomplete: 220+ completions via @codemirror/autocomplete — keywords, globals (print, pairs, require, pcall), libs coroutine/string/table/math/io/os/utf8/debug/package + snippets
• Snippets: function, local function, if, ifelse, fori, forp, while, repeat, local, print, ::label:: (trigger if → expands if ${cond} then … end)
• Highlighting: @lezer/highlight tags (controlKeyword, definitionKeyword, logicOperator, atom, variableName, labelName, propertyName, string, number, lineComment/blockComment/Shebang, arithmetic/bitwise/compare operators)
• Indentation: delimitedIndent per block (do/while/repeat/if/for/function/{}) + continuedIndent for else/elseif/until
• Folding: Chunk, Block, DoBlock, WhileBlock, RepeatBlock, IfStatement, ForStatement, FunctionBody, TableConstructor, LongString, BlockComment, Shebang
• Brackets & comment tokens: commentTokens {line:"--", block:{open:"--[[",close:"]]"}}, closeBrackets ["(","[","{",'"',"'"], indentOnInput for end/else/elseif/until

Usage

import { EditorView, basicSetup } from "codemirror"
import { lua } from "@fazelstudio/codemirror-lang-lua"

new EditorView({
  parent: document.body,
  doc: `print "Hello, Lua!"`,
  extensions: [basicSetup, lua()],
})

Autocomplete (new in 1.0)

lua() now ships with autocomplete out-of-the-box. No extra setup:

import { autocompletion } from "@codemirror/autocomplete"
new EditorView({
  extensions: [basicSetup, lua(), autocompletion()],
  // type `pri` → suggests `print`, `pairs`; `str.` → `string.find`, etc.
  // snippet: type `fori` → `for ${i} = ${1}, ${10} do … end`
})
// Disable if you bring your own completions:
lua({ enableCompletion: false })

API

lua(config?: LuaConfig) → LanguageSupport

interface LuaConfig { enableCompletion?: boolean } // default true

Create a LanguageSupport extension for Lua.

import {lua, luaLanguage, luaCompletion, luaCompletionList, luaHighlighting} from "@fazelstudio/codemirror-lang-lua"
lua() // with autocomplete
lua({enableCompletion:false}) // without
luaLanguage // LRLanguage
luaCompletion // CompletionSource (ifNotIn guarded)
luaCompletionList // raw 220+ completions
luaHighlighting // styleTags object

luaLanguage: LRLanguage

The underlying LRLanguage instance. Provides parser, languageData (comment tokens, indent, brackets, autocomplete).

• commentTokens: { line: "--", block: { open: "--[[", close: "]]" } }
• indentOnInput: /^\s*(end|else|elseif|until|\)|\])$/
• closeBrackets: ["(", "[", "{", '"', "'"]
• wordChars: "_"
• autocomplete: luaCompletion (via ifNotIn — disabled inside String/LongString/Comment)

Build

npm run build:grammar # lua.grammar -> src/parser.js
npm run build         # src/*.ts -> dist/*.js + .cjs + .d.ts (rollup)
npm test              # run fixture tests

Coverage

• 129 fixture tests in test/cases.txt (v0.1 92 → v1.0 129) — 40 checklist §6 + 89 edge/real-world
• Verified on real files: Kong/kong/db/schema/init.lua (78 kB, 0 ⚠ after fix, was 18), lua/lua/testes/literals.lua (11 kB), neovim Telescope snippet require("telescope.builtin").find_files() (now 0 ⚠, was ⚠ before 1.0 fix), LOVE & OpenResty samples

Known limitations

• Type analysis/inference is out of scope — this package only provides syntax highlighting, parsing, folding, indent & completions, not semantic analysis.
• String interpolation is not supported (Lua doesn't have it natively — use ..).
• Module/package system (require) is runtime-level, not part of the grammar (but parsed as prefixexp args).
• Binary literals (0b1010) and underscore separators (1_000) are parsed for editor convenience though not strictly Lua 5.4 spec (they are LuaJIT/5.4 compat extensions).

License

MIT © Fazel Studio